We have a board with different plugs.
I rearrange the wall art, brochures and books to highlight ones relevant to their language/country.
The food in the welcome basket is customized depending on where they're from. For example, French people tend to love the farmhose brown bread and salmon.
If there are children, I have one or two of lots of different drinks for them to try.
People from former British colonies would be more familiar with Irish things than other countries, such as remembering to flick a switch to turn on the hot water, so I give more detailed instructions to others.
If they are from a cold place, I keep the heat down. If from a warm place, I keep it warm and point out the heaters and use heavier duvets.
If sending messages to Americans, I use 12-hour times, others, 24-hour clock.
I try to use a few words in their language and change the way I write and speak, depending on how good their English is.